34 PKOGKESS OF MICROSCOPICAL SCIENCE. 



The Microscope in Leprosy. — This is a subject which has been gone 

 into very fully by Dr. Carter, of Bombay, in his paper this year read 

 before the Eoyal Medical and Chirurgical Society. After dealing with 

 some of the more medical portions of the subject, it stated that the 

 structural changes observed are due to exudation or deposit in the 

 skin and appertaining nerve-trunks of a firm, translucent, colourless, or 

 pale-reddish material, which may be distinguished by the borrowed 

 terms hyalin-fibroid and hyalin-granular. As regards the skin, con- 

 junctiva, and adjacent mucous membrane of the mouth and larynx, this 

 deposit (here hyalin-granular) first apjjears within or immediately 

 beneath the membrane proper ; accessory organs, and even the blood- 

 vessels, are secondarily involved, but it has been noticed that the 

 tactile corpuscles disappear before other less sentient elements. As 

 regards the nerves, this deposit (here hyalin-fibroid) first appears be- 

 tween the individual nerve-tubules, and within their sheath — i. e. the 

 neurilemma of the funiculus ; the outer envelope of connective tissue 

 is hardly changed. By accumulation of the new material the tubules 

 are separated, compressed, emptied, and eventually destroyed. The 

 microscojoic characters of this leprous deposit are then referred to. 

 The material looks exudative, but may be derived from proliferation 

 of connective-tissue corpuscles ; it undergoes slight development, and 

 is susceptible of degeneration. In sixteen autopsies of lepers con- 

 secutively dying in hospital, no trace of deposit was noticed in the 

 muscles, bones, or any of the viscera. The brain and spinal cord 

 were wholly free from such deposit, &c. 



Megeneration of the Ejpiilielium in the Web of a Frog's Foot. — Dr. 

 Klein, of the Brown Institute, gives an excellent account of Biesia- 

 decki's recent experiments on the above subject. He says that he uses 

 the web of the frog. The animal, slightly curarised, is placed on a 

 glass plate, its web is stretched over a cork ring fixed on the plate, 

 and a small drop of cantharidal collodion is allowed to flow over the 

 edge of the web, so that it affects both surfaces near the edge. The 

 part which is to be observed is covered with a small thin glass, a suffi- 

 cient quantity of solution of sulphate of sodium or common water 

 having been poured on the web. It can be examined under a magni- 

 fying power of 300-450. After two hours, the epidermis of the part 

 to which the cantharidal collodion had been applied is raised as a 

 blister, and the blood-vessels of the corium, arteries, and veins, as well 

 as capillaries, appear to be somewhat dilated. The upjier wall of the 

 blister consists either only of the epidermis, or of the epidermis and 

 the superficial layers of the rete Maljiighii, or it consists of the whole 

 epithelium. In any case, the wall of the blister must be removed 

 entire with great care. The most suitable cases for observation are 

 those in which, after the removal of the blister, the true corium is 

 exposed, and the circulation in the blood-vessels is unchanged. The 

 regeneration of the epithelium takes j^lace thus : — Soon after the re- 

 moval of the blister, the blood-vessels become dilated, the colourless 

 blood-corpuscles accumulate first in the veins, then also in the capil- 

 laries, and an abundant emigration of them follows. After six or 

 eight hours the corium contains numerous groups of colourless cor- 



